For many years, computer users have had the option of purchasing a digitizing tablet and stylus for their computers. A tablet and stylus allows the user to move the computer's cursor with a pen-shaped device called a stylus. When drawing sketches or creating other types of artwork on screen, a stylus can be used more naturally than a mouse or trackball or other type of input device.
Most styluses are sensitive to the “pressure” (i.e., force) with which the user applies the stylus to the tablet, and this force data is used by application software to determine characteristics such as line or brush width, darkness, or other quality that is applied to a digital canvas.
Many digitizing tablets use electromagnetic fields to determine the location of the stylus. The tablet is thus an active device that that has rows and columns of wires, or loops of wires, for generating the fields. The stylus includes electronics that interact with these fields.
Such digitizing tablets are provided as a separate devices for use with desktop computers. They are too large and cumbersome for portable use with a notebook computer. Even with a desktop computer, they can consume valuable space.
FingerSystems Inc. produces a product they call the i-pen, which (at least in some of its forms) is essentially an optical mouse shaped like a pen. It can be used with a special pad or on almost any surface. Its operation is relative-position and relative-orientation. Relative position means that there is no absolute coordinate system that it uses. Relative orientation means that movements up, down, left and right are interpreted according to the orientation of the device itself. This can be problematic, causing a user's writings to creep unexpectedly up or down because of how they hold it. It also skews sketches.
ANTO COMPONENTS (anoto.com) provides pen-and-paper based solutions for portable sketching. For example, the Logitech Digital Pen can be used to draw handwriting and sketches in real ink on “smart paper.” It is not even necessary to have a computer nearby. The smart paper has absolute position codes encoded all over its surface. These codes are in indicia that is generally invisible to the human eye. However, the Pen “sees” the absolute position codes on the smart paper and stores the handwriting and sketching gestures in the pen for later download to a computer.